time_second vs. time_uptime

[Jung-uk Kim]

On Friday 09 September 2005 05:48 pm, Brooks Davis wrote:
> On Fri, Sep 09, 2005 at 05:44:24PM -0400, Jung-uk Kim wrote:
> > If I read the source correctly, time_second can go backwards or
> > forwards when there is a leap second but time_uptime cannot.  Am
> > I right?  If my assumption is right, it seems we have some
> > misuses in kernel, e. g., sched_sync() in sys/kern/vfs_subr.c. 
> > It may not be critical but it worries me a little because a leap
> > second is scheduled to occur at the end of this year. ;-)
>
> Yes, uptime increases monotonically, but leap seconds and
> adjustments such as those made by ntpdate will make simple time
> values jump around.  This bit me when I first did the interface
> epochs since absolute times are not necessarily unique.

It seems the most commonly misused places are networks stacks.  It's 
understandable because time_uptime is relatively new. :-)

http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/kern/kern_tc.c.diff?r1=1.140&r2=1.141

Anyway let's start fixing!

Thanks,

Jung-uk Kim
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